Diane Wahlstad and biofiltration making plants suffer and causing algae?

[dw1305]

Hi all,

I don’t believe that removing bio media in the filter will reduce bio filtration, as there is plenty of beneficial bacteria in the substrate, plant and other surfaces as long as oxygenated water supply is unlimited.

I would tend to agree, my guess is that the microbial assemblage will be fairly closely matched to the amount of nutrients (carbon, nitrogen, oxygen etc ) in the system, it is back to Liebig's limiting nutrients, but this time for microbes. If we ensure that <"oxygen isn't the limiting nutrient"> then things aren't likely to <"spiral out of control">.

The advantage would be that a planted system you would have some spare nitrification capacity if the nitrogen or carbon input suddenly rose

but off photo period, bb is the only game in town to detoxify ammonia.

Plants will still take up some ions in the dark, we talked about the differences in <"active and passive uptake"> in <"iron deficiency">.

cheers Darrel

 

[dw1305]

Hi all,

This may be of more interest:

That is probably about as good as we are going to get.

I've found a review article Liu, J. et al. (2017 )<"Advanced nutrient removal from surface water by a consortium of attached microalgae and bacteria: A review"> Bioresource Technology 241, pp. 1127-1137 has a schematic figure of the composition of attached biofilms.


I'd guess in most cases that dark areas aren't an issue due to the biofloc effect and the turbidity of the waste water.

cheers Darrel

 

[Matti]

Walstad book cited many references from outdoor ecological studies, but glass box environment is very different from outdoor environment, and direct extrapolation of the results is not always relevant and may lead to wrong conclusion. For example, high nitrate and phosphate is often associated with algal boom in natural water bodies, but not so in planted aquariums.

The problem with aquariums is the lack of real data. There are a lot of opinions and believes , but few real theories or models that would have been tested, measured and published.
The great thing in Walstads book is that she has a tried to understand what happens in a planted tank by using real data and studies, albeit from outdoor ecosystems.
And her opinion that too strong filtration is not beneficial for plants makes sense, supported by her own experiments.
And she was right when se recommended using floaters to control nitrates. I added some Frogbits to my 55l and it's just insane how they take up nutrients! I used to dose Tropica Premium 3ml weekly, now I'm dosing 8ml the have the same nitrates levels around 10ppm.

​

 

[dw1305]

Hi all,

And she was right when se recommended using floaters to control nitrates. I added some Frogbits to my 55l and it's just insane how they take up nutrients!

You are talking <"to the converted">, I'm a <"Frogbit obsessive">, but it was Diana Walstad's <"aerial advantage"> that led to the <"Duckweed Index"> and eventually Limnobium laevigatum as my <"preferred "Duckweed">.

cheers Darrel

 

[jaypeecee]

Hi @dw1305 & Everyone,

We appear to have dismissed lighting as a potential inhibitor of nitrification in aquaria. Have I missed something? That's entirely possible as this is the first time I've been on UKAPS today.

JPC

 

[MichaelJ]

Hi all,
that led to the <"Duckweed Index"> and eventually Limnobium laevigatum as my <"preferred "Duckweed">.

Hi Darrel, Perhaps you should rename it the Frogbit index. I wish your advice on the "preferred duckweed" would have been more obvious to me before this happened



When the duckweed really gets going its really hard to get rid of... its almost out competing my Frogbit.

Cheers,
Michael

 

[erwin123]

Growing plants out of a hang on back filter is an alternative way of getting the 'aerial advantage' if you want some light to reach the plants in your tank. And I don't have to water my Monstera 🙂

 

[dw1305]

Hi all,

Perhaps you should rename it the Frogbit index. I wish your advice on the "preferred duckweed"

It would have been a lot easier. In <"some ways Duckweed"> (Lemna minor) is the <"perfect plant"> for the Duckweed Index but it also <"has some limitations">.

When the duckweed really gets going its really hard to get rid of... its almost out competing my Frogbit.

That is looking very healthy, plenty of nutrients in that tank. We may <"have a solution to your Duckweed removal issues">.

cheers Darrel

 

[dw1305]

Hi all,

Monstera prices have shot up in the last couple of years

They <"certainly have">.

I had a few stolen that were part of a old group of stems in my yard.
City life.

It is a shame, I used to belong to a <"Cycad growing group"> and about a third of the posts were to do with theft.

cheers Darrel

 

[dw1305]

Hi all,

One thing I might be harping on in the future is highly aerated aquarium water supercharges the bacteria in the filters and that seems to really polish the water clarity with no increase in filter or pump.

It is used a lot in <"waste water treatment"> in the <"activated sludge process">.

..... The prime metric in nitrification isn't actually the ammonia concentration, it is the dissolved oxygen level. As you have water with greater amounts of organic pollution its Biochemical Oxygen Demand (BOD) increases, BOD values range from clean water at below 5 mg/l dissolved oxygen up to about 600 mg/L in raw sewage. Water is fully saturated with oxygen at about 10 mg/L, so you can see that you would need to continually add oxygen for nitrification to occur......

cheers Darrel

 

[dw1305]

Hi all,

We appear to have dismissed lighting as a potential inhibitor of nitrification in aquaria. Have I missed something?

I couldn't find anything specifically for the microbial assemblage that occurs in aquarium filters. I think the answer looks to be that the nitrifying bacteria are inhibited by light, but that it probably doesn't have much effect, because the bacteria are effectively shielded within biofilms.

cheers Darrel

 

[Nick potts]

Hi all,

I couldn't find anything specifically for the microbial assemblage that occurs in aquarium filters. I think the answer looks to be that the nitrifying bacteria are inhibited by light, but that it probably doesn't have much effect, because the bacteria are effectively shielded within biofilms.

cheers Darrel

I would think that light inhibition would be inconsequential in aquariums. If you look at a lot of marine reef tanks for example, they rely on the biofiltration taking place on mostly exposed live rock, this rock is usually exposed to very high par and light in the UV spectrum but it doesn't seem to affect filtration.

 

[Matti]

Hi all,

You are talking <"to the converted">, I'm a <"Frogbit obsessive">, but it was Diana Walstad's <"aerial advantage"> that led to the <"Duckweed Index"> and eventually Limnobium laevigatum as my <"preferred "Duckweed">.

cheers Darrel

I see Frogbites as an alternative to massive water changes. You can dose ferts quite relaxed as you know that the floaters are using them like crazy! The only downside is my red plants that are not so red any more. But BBA has not returned, so Frogbites rule!

 

[MichaelJ]

That is looking very healthy, plenty of nutrients in that tank. We may <"have a solution to your Duckweed removal issues">.

Yes, the "duckweed index" works well for gauging nutrients levels - I am big fan! With regards to removing the duckweed, I sort of already went down the route of making it a regular part of my maintenance routine to net every floating plant except for the pennywort and rinse off the duckweed. That keeps it somewhat in check. The duckweed came in with some other plants long ago - so they are in the tanks somewhat unintentionally.

Cheers,
Michael

 

[_Maq_]

For example, high nitrate and phosphate is often associated with algal boom in natural water bodies, but not so in planted aquariums.

I find this a big mystery. Does anyone know why? Why do we so rarely encounter phytoplankton in aquaria?

 

[_Maq_]

The problem with aquariums is the lack of real data. There are a lot of opinions and believes , but few real theories or models that would have been tested, measured and published.
The great thing in Walstads book is that she has a tried to understand what happens in a planted tank by using real data and studies, albeit from outdoor ecosystems.
And her opinion that too strong filtration is not beneficial for plants makes sense, supported by her own experiments.

(1) Papers on outdoor ecosystems... If you truly read those papers, you'd see that many scientific experiments are performed in tanks made of glass, which are called ... hmm ... let me recall... yes - aquarium.
(2) I happened to read quite many of the papers Ms. Walstad added to her lists. Her selections of facts are strongly biased to support her stance. Actually, I caught her quoting a paper without context, while the paper as a whole arrived at exactly opposite conclusions. So, she went at great length to appear as a scientist, but in my opinion, she's not. (Besides, she never published any scientific paper.)
(3) Take her statements about submerged plants' preference for ammonia over nitrate. That is a gross simplification. If judged without context, then yes, taking ammonia and creating amino-acids from it is energetically less demanding. But in reality, it is subject to many other factors. pH is one among them. Nutritional status another one. Mineral content of the water is another. And light intensity is next one, and yet not the last one. The only correct answer to the question of ammonia or nitrate is - both should be available, and let each plant to choose.
(4) Have you read the list of plants which she kept in her tanks? If I were able to keep only such easy plants, I would not dare to provide advice to anyone, not to mention publishing "a scientific treatise".

 

[tiger15]

I find this a big mystery. Does anyone know why? Why do we so rarely encounter phytoplankton in aquaria?

One explanation is that most environmental studies were conducted either in waters without aquatic plants or in temperate zone where aquatic plants are seasonal. Without active growing aquatic plants for competition, high nitrate and phosphate is naturally associated with algal bloom. If more studies were conducted in tropical waters with perennial aquatic plants, the association may not be apparent.

 

[dw1305]

Hi all,

Have you read the list of plants which she kept in her tanks? If I were able to keep only such easy plants, I would not dare to provide advice to anyone, not to mention publishing "a scientific treatise".

I'd cut her a lot more slack than that, it <"may not be perfect">, but I still think it holds up pretty well and is one of the <"most useful books"> ever published for planted aquarium keepers.

cheers Darrel

 

[tiger15]

Her book was the first one I read on planted aquarium. Her book sounds scientific with references supporting every one of her viewpoints. While many concepts appear theoretically sound, they may not be relevant to glass box culture and cannot be validated in practice. For example, her recommendation for no water change approach by listing complete nutrient availability in fish food, waste and tap water. In practice, it rarely works out and an invitation for algae and deficiencies except for the easiest plants like Hornwort.